Ice cube making machine



Oct.

"L f I w ill; 47 i! l F/a/ 12mm,,

i I a g 6/ ICE CUBE MAKING MACHINE T. A. DWYER S Sheets-Sheet l /4 H "m7 .26 fl z i f I 22 6/ 32 5-:- za-z I: Z /3 5mm 2529 l 39 "ll I I I I 56i 55 55 38 i 46 E i J; lllh W THO/MA o H. o mom F/ G. 3 BY Gag 3.141%?ATTORNEY Oct. 11, 1966 Filed April 20, 1965 T. A. DWYER ICE CUBE MAKINGMACHINE 5 Sheets-Sheet 2 THmmsA. OWYfR BY M ATTORNEY Oct. 11, 1966 T. A.DWYER 3,277,661

ICE CUBE MAKING MACHINE Filed April 20, 1965 5 Sheets-Sheet S 8/4 74 6548a 43 V 4L2 4a m 64 INVENTOR. THaMAs'A. Dwyfl? ATTORNEY United StatesPatet 3,277,661 ICE CUBE MAKING MACHINE Thomas A. Dwyer, New York, N.Y.,assignor to Square Cube Corp., Long Island City, N.Y., a corporation ofNew York Filed Apr. 20, 1965, Ser. No. 449,437 1 Claim. (Cl. 62135) Thisinvention relates in general to ice cube making machines and moreparticularly to a novel control device for automatically cyclicallyproducing ice cubes in an ice cube making machine.

Machines have been provided which produce ice cubes in a periodic mannerby going through respective freezing and harvesting cycles; during theformer operation the ice cubes are produced and during the latteroperation the cubes are discharged by the machine into an appropriatereceptacle. In machines of the type described it is essential toaccurately initiate and terminate the respective freezing and harvestingcycles to insure optimum operation. Various types of control deviceshave been suggested for ice making machines. For example, in the machinedisclosed in Patent No. 3,009,336, issued to I. R. Bayston et al. onNovember 21, 1961, the duration of the freezing cycle is related to thecirculating water in the system.

More particularly, in the machine described in the aforementioned patentthe circulating water system includes a nozzle connected to the watersupply line. The nozzle ejects a stream of water in an arc-the radius ofthe arc varies with the pressure of the water. The path of thecirculating water additionally includes orifices in the ice cubefreezing compartments. As the cubes are produced the orifices areprogressively covered by the cubes thereby increasing the pressure inthe system. Thus, the water stream issuing from the nozzle at thebeginning of the freezing cycle (at low pressure) is directed in arecirculating path in the system; when the water pressure reachesincreased values at the end of the freezing cycle the water stream isthen directed to a drain. As the water in the system is drained out of areservoir, a switch, which is responsive to the water level in thereservoir, is actuated to terminate the freezing cycle. This latteroperation is accomplished by biasing the armature of the switch to anormally closed position by a spring. A pilot tank, which reflects theWater level in the reservoir, is similarly connected to the armature ofthe switch and is adapted to actuate the armature to open the switchwhen the water level in the pilot tank is above a predetermined height.In other words, the force of the spring is balanced against the weightof water in the pilot tank.

A severe disadvantage has been encountered in this type of arrangementbecause the force exerted by the spring varies with ambient temperature,age and other environmental factors, thereby giving rise toirregularities in the control of the machine by producing freezingcycles of varying duration rather than a set and fixed duration.Accordingly, the ice making machine of the aforementioned patentrequires substantial maintenance and repair since the tension in thespring must be constantly adjusted. Thus, the machine is extremelyinefficient in operation and uneconomical in use.

It is an object of the present invention to provide an improved controldevice for controlling the duration of the freezing cycle in anautomatic ice cube making machine.

It is another object of the present invention to provide a controldevice for controlling the duration of the freezing cycle in automaticice cube making machines which is efficient in operation and economicalto manufacture.

A preferred embodiment of the control device of the present inventionfor use in automatic ice cube making machine comprises first and secondserially connected thermostatically actuated switches. When thetemperature of the freezing compartment which produces the ice cubesreaches a first predetermined temperature of approximately 55 F. thefirst thermostatically actuated switch is operated to initiate thefreezing cycle. During the freezing cycle the first thermostaticallyactuated switch is again operated (when the temperature of the freezingcompartment drops to approximately 30 F.) to connect a source ofpotential across the second thermostatically actuated switch. When thetemperature of the freezing compartment drops to approximately 10 F., atwhich time the ice cubes will be completely formed, the secondthermostatically actuated switch is operated to terminate the freezingcycle and initiate the harvest cycle by applying the potential across apair of solenoids; one of said pair of solenoids controlling theentrance of water into the reservoir for the production of a new batchof ice cubes and the other of said pair of solenoids allowing hot gas tofiow through the evaporator coil to warm the freezing chamber. Thesecond thermostatically actuated switch is adapted to open the seriescircuit when the temperature of the freezing compartment reachesapproximately 50 F. The first thermostatically actuated switch isadapted to be operated to again initiate the freezing cycle when thetemperature of the freezing compartment reaches approximately 55 F.whereupon the cycle will repeat itself automatically.

It is a feature of the present invention to provide serially connectedthermostatically actuated switches to accurately control the duration ofthe freezing cycle in an automatic ice making machine.

Additionally, by utilizing the control device of the present invention,the volume of water required at the beginning of the freezing cycle neednot be more than the volume of Water actually frozen. This is to becontradistinguished from prior art type of ice making machines wherein avolume of water in excess of the volume of water actually frozen isutilized and the excess water is drained off at the termination of thefreezing cycle.

Thus, it is another feature of the present invention to provide acontrol device for automatic ice making machines wherein the cycles ofoperation are of substantially shorter duration than in ice makingmachines used heretofore since less water need be recirculated in thepresent invention.

The above and other objects and features of the present invention willbecome more apparent from a consideration of the following detaileddescription when taken in conjunction with the drawings in which:

FIG. 1 is a perspective view of an ice making machine having theimproved control means of the present invention therein;

FIG. 2 is a vertical sectional view of the ice making machine shown inFIG. 1 during the harvest cycle;

FIG. 3 is a vertical sectional view of the ice making machine shown inFIG. 1 during the freezing cycle;

FIG. 4 is a front elevational view of the machine shown in FIG. 1 duringthe harvest cycle with the cover plate removed;

FIG. 5 is a view similar to FIG. 4 but showing the arrangement of themachine during the freezing cycle;

FIG. 6 is a fragmental detail sectional view through a cell of thefreezing chamber with the parts in position during the freezing cycle;

FIG. 7 is a detailed sectional view of the freezing chamber taken alongline 77 of FIG. 6;

FIG. 8 is a schematic diagram of the refrigeration and water circulationsystems used in the machine shown in FIG. 1; and

FIG. 9 is a schematic circuit wiring diagram of the control device ofthe present invention.

The control device of the present invention is adapted to control theoperation of an ice making machine similar to the type disclosed in theaforementioned patent to Bayston et al. and shown herein in FIGS. 18.Thus, as shown in FIG. 1, the automatic ice making machine 19 comprisesan upper freezing portion 11 and la base portion 12. Machine is providedwith side walls 13 and a top Wall 14. It is to be understood that thewalls of the machine may be lined with a suitable insulating material(not shown) in the conventional manner. Base portion 12 is provided witha swinging insulated door 15 which is connected to machine 10 bysuitable hinges (not shown). A handle 16 is provided to facilitateopening and closing door 15. The interior of base portion 12 comprises abin 17 which receives and stores the ice manufactured in freezingportion 11. Bin 17 is provided with a pivoted front plate 18 which isengaged by brackets 19 on the inner surface of door 15 for tilting thefront of the ice bin upward to facilitate removal of the ice cubeswithin bin 17.

Freezing portion 11 of the machine, as shown in FIGS. 2-5, is providedwith a back wall 20, which extends between side walls 13, and a frontwall 21. A partition 22 extends between rear wall 20 and front wall 21and divides freezing portion or unit 11 into a freezing section 23 and acompressor section 24.

The freezing apparatus of automatic ice making machine 10 includes anevaporator unit denoted generally by the numeral 25. More particularly,evaporator or freezing chamber 25 comprises a top plate 26 andperpendicularly downwardly laterally and longitudinally extendingpartitions 27 which form a plurality of individual open-bottom, freezingcells 28. It is to be understood that the cells 28 defined by top plate26 and partitions 27 are cubicals in which the ice cubes are produced.

A closure plate 29, which is mounted in a frame 30, is adapted to closethe open bottoms of freezing cells 28, as shown in FIG. 3. Frame 30 ispivotable about a pivot pin 31 and is connected thereto by a bracket 32.Thus, closure plate 29 may be respectively raised to a cell closingposition during the freezing cycle of operation, as shown in FIG. 3, ormay be lowered to an ice dispensing position during the harvest cycle ofoperation, as shown in FIG. 2, to permit discharge of the ice cubes fromcells 28. A motor 33 (shown in the schematic circuit wiring diagram ofFIG. 9 only) is operable to raise and lower closure plate 29. The outputshaft 34 (FIGS. 25) of motor 33 may be rotated in either the clockwiseor the counter-clockwise direction to effect raising and lowering ofplate 29. The links 35 are fixedly connected to the ends of shaft 34 andare rotatable therewith. A spring 36 is connected between the lower endof each link 35 and frame 30, as shown in FIGS. 25. Shaft 34 may besupported in freezing section 23 by any conventional means as by cars(not shown) depending from top wall 14 and rotatably receiving shaft 34therethrough. Clockwise rotation of shaft 34-, as taken in FIGS. 2-5,will cause frame 30 to pivot about pin 31 to thereby raise closure plate29 into abutment with partitions 27 to close the open bottoms of cells28. Springs 36 will be tensioned, as shown in FIG. 5, to maintainclosure plate 29 tightly against the bottoms of partitions 27. Theleading face 35a of one of the links 35 is adapted to move the arm of atoggle switch 37 when link 35 is rotated to the position shown in FIG.5. Counter-clockwise rotation of shaft 34, as taken in FIGS. 2-5 willcause links 35 to rotate counter-clockwise to lower frame 30 to againopen the bottoms of cells 28 and allow the ice cubes to be releasedtherefrom. Cubes 39 will be released from cells 28 and strike plate 29to thereupon slide down plate 29 into chute 38 which communicates withbin 17. An extension bar 40 (FIG. 4) which extends outwardly from link35, is adapted to communicate with toggle switch 37 4; when the link isin the down position to move the arm of toggle switch 37 as described inmore detail hereinbelow. It is to be noted that link 35 is provided witha cam surface 3512 which is adapted to abut against and strike closureplate 29 to facilitate the opening of cells 28 after the ice cubes havebeen produced.

Machine 10 is provided with a connection 41 which is adapted to beconnected to a source of water to provide the fluid necessary for theproduction of the ice cubes. Connection 41 is connected, through asolenoid actuated valve 42 (FIGS. 4 and 5) to a line 43 which dischargesonto closure plate 29 through a header 43a. Thus, the water will flowdown plate 29 and through holes 45 in closure plate 29 into a reservoir46 which depends from frame 30. The leading edge 46a of reservoir 46projects outwardly of plate 29 to define a marginal opening 46btherebetween. Hence, in addition to entering reservoir 46 through holes45, the water will also enter the reservoir through opening 461).Connection 41 is also connected,

through a line 47 (FIG. 8) and a pressure controlled.

valve 48, to a tube 49 in an auxiliary water-cooled heat exchanger 50 asdescribed more fully hereinbelow. Water flowing through tube 49 isdischarged through an outlet tube 51 into the drain of the machine (notshown). As is conventional, the operation of valve 48 is dependant uponrefrigerant pressure and is connect-ed to a refrigerant reservoir 52through a pressure control line 53. Thus, valve 48 will open and supplycold water to cooler 50 when the refrigerant pressure in control line 53reaches a pre-set limit.

As shown in FIGS. 6 and 7, top plate 26 is provided with bores 44therethrough which communicate with cells 28 to thereby provide airvents for the cells. Reservoir or tank 46 is supplied with apredetermined volume of water prior to the actual freezing cycle. Thiswater is recirculated through the freezing chambers, as noted below,until the ice cubes are produced. As one of the features of the presentinvention the volume of water introduced into the tank is substantiallyequal to the amount of water required to produce the ice cubes therebyeliminating the draining of excess water after the freezing cycle hasbeen completed. Thus, since substantially less Water is recirculatedthrough the system in the machine described, the freezing cycle may beof shorter duration than the freezing cycles of machines utilizedheretofore.

Prior to the initiation of the freezing cycle, water is allowed to flowinto tank 46 by the method described below when the tank is in the downposition. An overflow tube 55 in reservoir 46 communicates with a draintube 56 which, in turn, is adapted to be connected to a drain externalof the machine. Thus, Water will flow into tank 46 until the level ofthe water in the tank reaches the top of drain tube 55 at which time thewater will overflow into drain tube 55 thereby assuring that the waterin the tank remains at a predetermined level. In the present inventionthis predetermined level of water, as noted above, corresponds to theexact volume of Water required to produce the ice cubes in cells 28. Itis to be noted that the front Wall 4611 of tank 46 includes a top edgewhich extends substantially above tube 55 when the tank is in the downposition to assure that the water will remain in tank 46 during thefilling operation.

A water pump 54 is connected to tank 46 and includes an inlet whichcommunicates with the bottom of tank 46. The outlet of pump 54 isconnected to a feeder pipe 56, as shown in FIGS. 2 and 3. Feeder pipe 56communicates with the circular water supply tubes 57 which extendlongitudinally below closure plate 29. Each of the water supply tubes57, as shown in FIGS. 6 and 7, are provided with the central transverseapertures 58 which are in alignment with the corresponding apertures 59in plate 29. It is to be noted that a plurality of such apertures 58 and59 are provided and are positioned so each aperture 58 and 59 will beapproximately centrally located in the bottom of a cell 28 when theclosure plate is in bottom-closing position. When pump 54 is operating,water will be pumped through feeder pipe 56 into tubes 57 and throughapertures 58 and 59 into the cells 28. Thus, the water will spurt upthrough closure plate 29 and will begin to form the ice cubes on thewalls of cells 28. The water which is not immediately frozen will fallthrough holes 45 in plate 29 back into tank 46 to be recirculated again.Thus, the water in tank 46 will be recirculated until frozen into icecubes. The end of pipes 57 are provided with a transverse aperture 60(FIG. 6) so the water which does not reach cells 28 will fall back intothe tank 46.

The refrigeration system of ice making machine is illustrated in detailin schematic form in FIG. 8 and the compressor portion of the system isindicated generally by the numeral 61 in FIGS. 25. Compressor 62compresses the gaseous refrigerant which fiows through a compressoroutlet 63 to a condensing coil 64. A fan 65, contained withincompartment 24, is positioned to blow air across the condensing coil 64in a conventional manner. The refrigerant, which leaves condensing coil64 as a liquid, flows through a pipe 100 and auxiliary heat exchanger 50which consists of the double coil, as noted above, wherein water ispassed through the complementary coil to remove heat from therefrigerant. A pipe 66 connects auxiliary heat exchanger 50 to an inleton the refrigerant reservoir 52. As is conventional in machines of thistype, a line 67 extends from the outlet of reservoir 52, through a heatexchanger 68 and an expansion valve 69 to a serpentine evaporator coil70 which is mounted on the top plate 26 of the evaporator unit. Therefrigerant is returned to an inlet 71 on compressor 62 via the returnline 72 which extends through heat exchanger 68. Expansion valve 69 iscontrolled by a thermostat 73, located on the return line 72, in theconventional manner. A hot gas bypass pipe 74 extends from outlet 63 oncompressor 62, through a hot gas solenoid actuated valve 75 toevaporator coil 70.

The operation of the above-described system is conventional. Thus, theliquified cooled refrigerant entering reservoir 52 will be supplied,through heat exchanger 68, to expansion valve 69. The expansion valvewill supply the refrigerant to the evaporator coil 70 in the form of agas which will cool the freezing compartment containing the cells 28therein thereby producing the ice cubes. After the freezing cycle isterminated, solenoid actuated valve 75 will be operated to allow hotgases to enter the coil 70 to facilitate warming of the freezing chamberand release of the ice cubes therefrom. It is to be understood thatafter termination of the freezing cycle the closure plate will have beenlowered to allow the ice cubes falling thereupon to be dispensed fromthe freezing portion 11 of machine 10.

Control system As noted above, automatic ice making machines usedheretofore have included inaccurate control devices for determining theduration of the freezing cycle. One such device included the use of apilot tank and pressure nozzle system wherein the pressure was dependentupon the ice cubes being formed in the freezing unit of the machine.However it was found that this was an extremely inaccurate andineflicient device.

In accordance with the present invention, the control system, asillustrated in FIG. 9, includes leads 77 and 78 which may terminate in aconventional male plug end which are adapted to be connected to aconventional wall outlet. Thus, the source of potential is representedby generator 103. Compressor 62 and fan 65 are connected across leads 7and 8 by the respective leads 79 and 80. Lead 77 is connected toterminal 1 of a toggle switch 76. The armature of toggle switch 76 isconnected to terminal 1 and is movable between terminals 2 and 3.

A biasing spring 82 normally biases the armature of switch 76 intocontact with terminal 3 thereby connecting terminals 1 and 3 together. Athermostatically controlled switch 81 is serially connected in lead 77between source 103 and circuit elements 62 and 65. The thermostat 81a islocated adjacent the top of bin 17 of ice machine 10 and, when the icecubes reach the level of the thermostat 81a the thermostat will beactuated to open switch 81 and prevent further operation of the machineuntil a sufiicient amount of cubes have been removed from the bin toallow the thermostat to warm up.

A lead 83 connects terminal 3 of switch 76 to one terminal of thesolenoid 42 which controls the activation of the water valve; the otherterminal of solenoid 42 is connected to lead 78. Solenoid 75, whichcontrols the flow of hot gases to evaporator coil 70, is connectedbetween lead 83, by a lead 84, and lead 78. Water pump 54 is connectedbetween terminal 2 of switch 76, by a lead 85, and lead 78. Toggleswitch 76 is actuated when frame 30 is moved to the upper orbottom-closing position. Thus, a bracket 85 (FIGS. 4 and 5) is connectedto frame 30 as by screws 86 and is positioned so when the frame 30 ismoved to the upper position the top edge of bracket 85 will engage thearm of toggle switch 76 to thereby move the armature of toggle switch 76to connect terminals 1 and 2 together. When frame 30 is lowered, biasingspring 82 will again cause terminal 1 to be connected to terminal 3.

Toggle switch 37 comprises two single-pole doublethrow switches mountedon a common base. Terminals 1, 2 and 3 comprise one switch and terminals4, 5 and 6 comprise the other switch. Terminal 2 is adapted to beconnected to either terminal 1 or terminal 3 and terminal 5 is adaptedto be connected to either terminal 4 or terminal 6. When the frame 30 isin the lower or ice dispensing position toggle switch 37 will be in theposition shown in FIG. 9; that is, terminals 2 and 5 will respectivelybe connected to terminals 1 and 6. When frame 30 is raised to the upperposition switch 37 will be actuated by edge 35a of link 35 to throw thearmatures of the switches comprising toggle switch 37 to the otherposition whereupon terminal 2 will be connected to terminal 3 andterminal 5 will be connected to terminal 4. It is to be understood thatwhen the frame is again lowered, extension 40 will re-set toggle switch37 to the position shown in FIG. 9. Terminal 6 is connected, through afield widing 87 of motor 33 to motor 33. The other end of motor 33 isconnected to lead 78 by a lead 88. The common terminal 5 of switch 37 isconnected to a terminal 3 of a thermostatically actuated switch 89 by alead 90. Terminal 4 is unconnected. Terminal 3 of switch 37 is connectedthrough another field winding 87a of motor 33 to the same terminal ofmotor 33 that field winding 87 is connected to. A lead 102 is connectedbetween terminal 3 of toggle switch 37, through a normally open pushbutton 91, to a lead 92 which in turn is connected to lead 84. Commonterminal 2 of toggle switch 37 is connected to lead 102 between pushbutton 91 and lead 92 by a lead 93. Terminal 1 of switch 37 isunconnected. When current flows through field winding 87, motor 33 willbe actuated to raise frame 30 and a tank 4-6 so closure plate 29 sealsthe bottom of cells 28. When field winding 87a is energized motor 33will be operable to lower frame 30 to allow the ice cubes to bedischarged from cells 28. When both fields are energized the frame willremain in its lower position.

The thermostat bulb 89a of thermostatically controlled switch 89 islocated on the evaporator unit 25 of the ice machine. Switch 89comprises three terminals respectively marked 1, 2 and 3 and includes anarmature which is connected to terminal 2 and which is movable toconnect terminal 2 to either terminal 1 or to terminal 3 in response tocontrols from thermostat bulb 89a. Thus, in the present embodimentterminal 2 is adapted to be connected to terminal 3 when the temperatureof the evaporator unit reaches approximately 55 F. On the other hand,terminal 2 is adapted to be connected to terminal 1 when the temperatureof the evaporator unit 25 is lowered to approximately 30 F. Terminal 2is connected directly to lead 77 by a lead 94. Terminal 1 of switch 89is serially connected to one terminal of a two terminal thermostaticallycontrolled switch 95. The operation of switch 95 is controlled by athermostat bulb 95a which is similarly located on unit 25. The otherterminal of switch 95 is connected to lead 92. Switch 95 is adapted toconnect terminal 1 to terminal 2 when the temperature of the evaporatorunit 25 reaches approximately F. and is further adapted to break thecircuit between terminals 1 and 2 of switch 95 when the temperature ofthe unit 25 reaches approximately 50 F.

In describing the operation of the present control system it is to beassumed that the device has been in operation for an interval of timeand that the harvest cycle has just been initiated so ice cubes 39 arebeing discharged and the hot gas is beginning to flow through evaporatorcoil 70 to heat up evaporator unit 25. It

is further to be understood that frame 30 is in its lower position soterminal 1 of toggle switch 76 is connected to terminal 3 and terminals2 and 5 of toggle switch 37 are respectively connected to terminals 1and 6. However, terminal 2 of switch 89 will be connected to terminal 1and terminal 1 of switch 95 will be connected to terminal 2 of switch 95since the freezing chamber has not heated sufliciently to cause switches89 and 95 to be operated to their other positions. For this casesolenoids 42 and 75 will be actuated to operate their respective valuesto respectively allow water to flow into tank 46 and hot gas to flowinto evaporator coil 70. That is, the source of potential across leads77 and 78 will be applied to solenoid 42 through lead 77, terminals 1and 3 of switch 76, lead 83, and lead 78. Similarly, the source ofpotential will be applied to solenoid 75 through lead 77, terminals 1and 3 of switch 76, lead 83, lead 84, and lead 78. It is assumed for allthese cases that bin switch 81 is closed. When the temperature ofevaporator unit reaches approximately 50 F. switch 95 will be actuatedto break the circuit between terminals 1 and 2. Further heating of theunit will cause thermostat bulb 89a to actuate thermostaticallycontrolled switch 89 to connect terminals 2 and 3 together therebyenergizing motor 33 through the circuit comprising lead 77, lead 94,terminals 2 and 3 of switch 89, lead 90, terminals 5 and 6 of toggleswitch 37, field 87, motor 33 and leads 88 and 87. This will cause frameto be raised to the upper position wherein closure plate 29 seals thebottom of cells 28. It is to be noted that the time interval requiredfor the harvesting cycle (i.e., the time required to heat up thermostatbulb 89a sufficiently to connect terminals 3 and 2) will be greater thanthe time interval required to fill tank 46 with the required volume offluid. In other words at the time switch 89 is actuated to cause thetank to be raised water will be overflowing through the overflow pipe 55thereby insuring that the required volume of water has been received intank 46. When frame 30 has been moved to the upper position toggleswitch 76 will be actuated by bracket 85 to connect terminal 1 toterminal 2 thereby breaking the connection between terminals 1 and 3 anddeenergizing solenoids 42 and 75 to respectively stop the flow of waterinto the system and cut-off the hot gases flowing through evaporatorcoil 70. Moreover, toggle switch 37 will be actuated by the leading edgea of link 35 to connect terminal 2 to terminal 3 and terminal .5 toterminal 4. However, field 89 will not be energized at this time sincethere is no connection between terminal 2 of switch 37 and the source ofpotential.

Pump 54 will be energized through the circuit comprising lead 77,terminals 1 and 2 of switch 76, lead 85, and lead 78 to thereby begin torecirculate the water in the system. As the refrigerent flows throughevaporator coil 70, the temperature in. unit 25 begins to decrease andthe 8 ice cubes will be formed within cells 28 in the aforementionedmanner. Switch 89 will be actuated when the temperature reachesapproximately 30 F. to thereby connect terminals 1 and 2 of switch 89together. In accordance with the present embodiment, ice cubes will becompletely formed by the time the temperature in unit 25 reachesapproximately 10 F. Thus, when the evaporator unit does reach theaforementioned 10 F. switch will be actuated to connect terminal 1 toterminal 2. When the aforementioned operation occurs, the freezing cyclewill be terminated and the harvesting cycle will be initiated becausemotor 33 will be energized through the circuit comprising lead 77, lead94, terminals 1 and 2 of switch 89, lead 96, terminals 1 and 2 of switch95, lead 92, lead 102, lead 93, terminals 2 and 3 of toggle switch 37,field 89, motor 33 ,and leads 88, and 78 to lower plate 29. Moreover,solenoids 42 and 75 will be energized through the circuit comprisingenergized lead 92, lead 84, and leads 83 and 78. As frame 30 is loweredthe armature of switch 76 will be biased to connect terminal 1 toterminal 3 thereby directly connecting solenoids 42 and 75 across thesource of potential through the circuit noted above. Moreover extension40 will connect terminals 2 and 5 of toggle switch 37 to the respectiveterminals 1 and 6. However, field winding 87 will not be energized atthis time since terminal 2 of switch 89 is connected to terminal 1. Thecubes will then be discharged in the above described manner and the hotgas flowing through evaporator coils 70 will again heat up the chamber.When the temperature reaches approximately 50 F. switch 95 will open andwhen the temperature further increases to 55 F. switch 89 will beactuated to connect terminal 2 to terminal 3 thereby again initiatingthe freezing cycle.

The above described operation has assumed that the machine has beenworking for an interval of time; how ever, if the machine is firstplugged in then an additional step must initially be performed beforethe machine can begin its automatic operation. If it is assumed that theconditions of the control system are as shown in FIG. 9 then as soon asthe machine is connected across a source of potential frame 30 will tendto rise since winding 87 of motor 33 will be energized through theaforenoted circuit before any water has been introduced into themachine. To prevent this occurrence push-button 91 is operated tothereby energize winding 89 through the circuit comprising lead 92, lead102, push-button 91, field winding 89, motor 33 and lead 88. Thus, bothfield windings 87 and 89 will be energized thereby preventing the motorfrom operating frame 30 to the upper position. That is, when both fieldwindings are energized the weight of frame 30 and the elements connectedthereto will maintain the plate in the lower position. The plate willalso move to the lower position if both field windings are energized ifthe plate is in any interemdiate position between the lower and theupper position or even in the upper position. Thus, the operator willmaintain button 91 closed until he observes water flowing out of theoverflow pipe 55 thereby signifying that the required volume of waterhas been received in tank .6. Thereupon, pushbutton 91 may be releasedand the freezing cycle will be initiated and the operation of themachine will be as noted above.

Thus, a control system for an ice making machine has been provided whicheliminates the pilot tank and double chambered receptacle heretoforeused and the attendant inaccuracies in the freezing cycle which wasassociated with these devices and has substituted therefor an accurateand economical control device for maintaining a freezing cycle of fixedduration.

While a preferred embodiment of the present invention has beendescribed, it will become obvious to those skilled in the art that minormodifications may be made therein without departing from the spirit orscope of the present invention.

What is claimed is:

An automatic ice cube making machine of the type including a freezingchamber having a plurality of open bottom individual cells in heatexchange relation with a refrigerant evaporator; a closure plate movablebetween a cell-closing position whereby the closure plate substantiallycloses the open bottom of said plurality of cells during the freezingcycle of the evaporator and an ice cube discharge position whereby theclosure plate opens the bottom of the plurality of cells during theharvest cycle of the machine; motor means for moving said closure platebetween cell-closure position and ice cube discharge position; tankmeans for holding a volume of water substantially equal to the volume ofwater required for producing the ice cubes, overflow means in said tankfor maintaining the volume of water at said predetermined limit; supplymeans for controlling the supply of water to said tank; recirculationmeans for recirculetting the water in said tank through the plurality ofcells during said freezing cycle; a source of potential; and controlmeans responsive to a predetermined temperature in said freezing chamberfor terminating the freezing cycle of said evaporator and connectingsaid source of potential across said motor means to energize said motormeans to move said closure plate to said ice cube discharge position,wherein said control means includes a first thermostatically actuatedswitch connected to said source of potential and a secondthermostatically controlled switch serially connected between said firstthermostatically controlled switch and said motor means, whereby saidfirst thermostatically controlled switch connects said source ofpotential across said second thermostatically controlled switch when thetemperature in said freezing chamber reaches a first temperature abovesaid predetermined temperature, and said second thermostaticallycontrolled switch connects said source of potential across said motormeans When the temperature in said freezing chamber reaches saidpredetermined temperature.

References Cited by the Examiner UNITED STATES PATENTS 2,687,019 8/1954Swenson 62l35 X 3,009,336 11/1961 Bayson et al. 62347 X 3,045,439 7/1962 Alt 62-348 X 3,045,440 7/ 196-2 McGraty et al 62-347 X ROBERT A.OLEARY, Primary Examiner. W. E. WAYNER, Assistant Examiner.

